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A028970 Numbers represented by quadratic form with Gram matrix [ 3, 1, 1; 1, 3, 1; 1, 1, 3 ]. 0
0, 3, 4, 7, 8, 11, 12, 15, 16, 19, 23, 24, 27, 28, 31, 32, 35, 36, 39, 40, 43, 44, 47, 48, 51, 52, 56, 59, 60, 63, 64, 67, 68, 71, 72, 75, 76, 79, 83, 84, 87, 88, 91, 92, 96, 99, 100, 103, 104, 107, 108, 111, 112, 115, 116, 119, 123, 124, 127, 128, 131, 132, 135, 136 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..64.

MAPLE

L := [seq(0, i=1..1)]: for x from -20 to 20 do for y from -20 to 20 do for z from -20 to 20 do if member(3*x^2+2*x*y+2*x*z+3*y^2+2*y*z+3*z^2, L)=false then L := [op(L), 3*x^2 +2*x*y+2*x*z+3*y^2+2*y*z+3*z^2] fi: od: od: od: L2 := sort(L): for i from 1 to 100 do printf(`%d, `, L2[i]) od:

CROSSREFS

Sequence in context: A227148 A026444 A003171 * A309388 A188259 A058235

Adjacent sequences:  A028967 A028968 A028969 * A028971 A028972 A028973

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from James A. Sellers, May 31 2000

STATUS

approved

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Last modified August 5 14:29 EDT 2021. Contains 346469 sequences. (Running on oeis4.)